There's just one small atom in this engine, but it's one giant leap for mankind. Physicists have finally built the single-atom engine -- a working engine that is made up of only one atom.
Previously, the best physicists could manage was an engine made up of 10,000 particles, according to Popular Mechanics.
The single-atom engine works in a similar way to a car engine, transforming thermal energy into mechanical energy. It is similar to a classic four-stroke car engine, which works by:
1. taking in a fuel mixture
2 compressing the fuel mixture using a piston
3. igniting the fuel
This pushes the piston back up, because the heat causes the fuel mixture to expand. It is this step that generates useful work since it is here that heating forcefully causes the piston to return to its original position (ie. thermal energy is converted into mechanical energy).
4. expelling exhaust
The new single atom engine, or nano-engine, follows a four-stroke process that closely parallels the classic car engine.
The atom is trapped in a cone of electromagnetic radiation. Physicists focus two laser beams on the cone. One beam heats the cone, and the other, applied closer to the base, uses Doppler cooling to cool it.
The particle is thus subjected to a thermodynamic cycle. It moves back and forth within the trap, thus "replicating the stroke of a typical engine."
"Because this heating and cooling slightly changes the size of the atom (more exactly, it alters the fuzzy smear of probability of where the atom exists), and the cone fits the atom so snuggly, the temperature change forces the atom to race back and forth along the length of the cone as the atom expands and contracts."
